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#ifndef AUTH_MD5_H
#define AUTH_MD5_H
/* ========================================================================== **
*
* MD5.h
*
* Copyright:
* Copyright (C) 2003, 2004 by Christopher R. Hertel
*
* Email: crh@ubiqx.mn.org
*
* $Id$
*
* -------------------------------------------------------------------------- **
*
* Description:
* Implements the MD5 hash algorithm, as described in RFC 1321.
*
* -------------------------------------------------------------------------- **
*
* License:
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* -------------------------------------------------------------------------- **
*
* Notes:
*
* None of this will make any sense unless you're studying RFC 1321 as you
* read the code.
*
* MD5 is described in RFC 1321.
* The MD*4* algorithm is described in RFC 1320 (that's 1321 - 1).
* MD5 is very similar to MD4, but not quite similar enough to justify
* putting the two into a single module. Besides, I wanted to add a few
* extra functions to this one to expand its usability.
*
* There are three primary motivations for this particular implementation.
* 1) Programmer's pride. I wanted to be able to say I'd done it, and I
* wanted to learn from the experience.
* 2) Portability. I wanted an implementation that I knew to be portable
* to a reasonable number platforms. In particular, the algorithm is
* designed with little-endian platforms in mind, but I wanted an
* endian-agnostic implementation.
* 3) Compactness. While not an overriding goal, I thought it worth-while
* to see if I could reduce the overall size of the result. This is in
* keeping with my hopes that this library will be suitable for use in
* some embedded environments.
* Beyond that, cleanliness and clarity are always worth pursuing.
*
* As mentioned above, the code really only makes sense if you are familiar
* with the MD5 algorithm or are using RFC 1321 as a guide. This code is
* quirky, however, so you'll want to be reading carefully.
*
* Yeah...most of the comments are cut-and-paste from my MD4 implementation.
*
* -------------------------------------------------------------------------- **
*
* References:
* IETF RFC 1321: The MD5 Message-Digest Algorithm
* Ron Rivest. IETF, April, 1992
*
* ========================================================================== **
*/
/* #include "auth_common.h" This was in the original. */
#include <inttypes.h> /* This was not... */
/* -------------------------------------------------------------------------- **
* Typedefs:
*/
typedef unsigned char uchar; /* Added uchar typedef to keep as close to the
original as possible. */
typedef struct
{
uint32_t len;
uint32_t ABCD[4];
int b_used;
uchar block[64];
} auth_md5Ctx;
/* -------------------------------------------------------------------------- **
* Functions:
*/
auth_md5Ctx *auth_md5InitCtx( auth_md5Ctx *ctx );
/* ------------------------------------------------------------------------ **
* Initialize an MD5 context.
*
* Input: ctx - A pointer to the MD5 context structure to be initialized.
* Contexts are typically created thusly:
* ctx = (auth_md5Ctx *)malloc( sizeof(auth_md5Ctx) );
*
* Output: A pointer to the initialized context (same as <ctx>).
*
* Notes: The purpose of the context is to make it possible to generate
* an MD5 Message Digest in stages, rather than having to pass a
* single large block to a single MD5 function. The context
* structure keeps track of various bits of state information.
*
* Once the context is initialized, the blocks of message data
* are passed to the <auth_md5SumCtx()> function. Once the
* final bit of data has been handed to <auth_md5SumCtx()> the
* context can be closed out by calling <auth_md5CloseCtx()>,
* which also calculates the final MD5 result.
*
* Don't forget to free an allocated context structure when
* you've finished using it.
*
* See Also: <auth_md5SumCtx()>, <auth_md5CloseCtx()>
*
* ------------------------------------------------------------------------ **
*/
auth_md5Ctx *auth_md5SumCtx( auth_md5Ctx *ctx,
const uchar *src,
const int len );
/* ------------------------------------------------------------------------ **
* Build an MD5 Message Digest within the given context.
*
* Input: ctx - Pointer to the context in which the MD5 sum is being
* built.
* src - A chunk of source data. This will be used to drive
* the MD5 algorithm.
* len - The number of bytes in <src>.
*
* Output: A pointer to the updated context (same as <ctx>).
*
* See Also: <auth_md5InitCtx()>, <auth_md5CloseCtx()>, <auth_md5Sum()>
*
* ------------------------------------------------------------------------ **
*/
auth_md5Ctx *auth_md5CloseCtx( auth_md5Ctx *ctx, uchar *dst );
/* ------------------------------------------------------------------------ **
* Close an MD5 Message Digest context and generate the final MD5 sum.
*
* Input: ctx - Pointer to the context in which the MD5 sum is being
* built.
* dst - A pointer to at least 16 bytes of memory, which will
* receive the finished MD5 sum.
*
* Output: A pointer to the closed context (same as <ctx>).
* You might use this to free a malloc'd context structure. :)
*
* Notes: The context (<ctx>) is returned in an undefined state.
* It must be re-initialized before re-use.
*
* See Also: <auth_md5InitCtx()>, <auth_md5SumCtx()>
*
* ------------------------------------------------------------------------ **
*/
uchar *auth_md5Sum( uchar *dst, const uchar *src, const int len );
/* ------------------------------------------------------------------------ **
* Compute an MD5 message digest.
*
* Input: dst - Destination buffer into which the result will be written.
* Must be 16 bytes, minimum.
* src - Source data block to be MD5'd.
* len - The length, in bytes, of the source block.
* (Note that the length is given in bytes, not bits.)
*
* Output: A pointer to <dst>, which will contain the calculated 16-byte
* MD5 message digest.
*
* Notes: This function is a shortcut. It takes a single input block.
* For more drawn-out operations, see <auth_md5InitCtx()>.
*
* This function is interface-compatible with the
* <auth_md4Sum()> function in the MD4 module.
*
* The MD5 algorithm is designed to work on data with an
* arbitrary *bit* length. Most implementations, this one
* included, handle the input data in byte-sized chunks.
*
* The MD5 algorithm does much of its work using four-byte
* words, and so can be tuned for speed based on the endian-ness
* of the host. This implementation is intended to be
* endian-neutral, which may make it a teeny bit slower than
* others. ...maybe.
*
* See Also: <auth_md5InitCtx()>
*
* ------------------------------------------------------------------------ **
*/
/* ========================================================================== */
#endif /* AUTH_MD5_H */
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